7.4: The structure of the Heart Flashcards
Overall structure
The heart is made of two separate pumps lying side by side.
The LEFT side deals with oxygenated blood from the lungs
The RIGHT side deals with deoxygenated blood from the body
Characteristics of the Pumps
Each have TWO chambers:
- The atrium - Thin walled and elastic which stretches as it collects blood
- The ventricle - much thicker muscular wall and contracts strongly to pump blood a distance, either to the lungs or the rest of the body
Reason behind having two pumps
The blood needs to return in order to become re-pressurised to get re-distributed around the body
Difference between the right side and the left
The right ventricle pumps blood only to the lungs, and has a thinner wall
The left ventricle pumps blood to the entire body, and has a much thicker wall to enable it to contract and create large pressure.
Valves on either side of the heart
The Bicuspid valve is on the LEFT, between the left atrium and the left ventricle
The Tricuspid valve is on the RIGHT, between the right atrium and the right atrium
They ensure blood only pumps in one direction
4 Vessels connected to the heart
Aorta - connected to the left ventricle and carries oxygenated blood to all parts of the body (except lungs)
Pulmonary vein - Connected to the left atrium and brings oxygenated blood back from the lungs
Vena Cava - Connected to the right atrium and brings deoxygenated blood back from the tissues of the body (Except lungs)
Pulmonary artery - Connected to the right ventricle where it carries deoxygenated blood to the lungs, where its oxygen is replenished
How is the heart supplied with oxygen
The heart is supplied with oxygen through the coronary arteries which branch off the aorta.
Blockage = muscle cells are unable to respire and die
